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Technical English - I 5th week

SURVEYING AND MAPPING

surveying / position / natural / man made / feature / equipment / mapping

What is surveying? It is the art of defining the positions of natural and man-made features on the Earth’s surface.

Basic Tasks and Features in Surveying:

Measurements

Surveying tools and equipment

Evaluation of survey data

Mapping

distance / elevation / angle / coordinates

Basic Engineering measurements: Distance Elevation Angle Coordinates (X/Y or Lat/Long etc.)

distance interval length space

Elevation (vertical position) is the height of a point relative to some reference point

Today’s Engineering Survey Tasks Cadastral surveying Area calculations Complex volume calculations Stockpile surveys Cut / excavation / fill calculations (Surveying for landfill sites) Slope measurements Cross and long sections Aerial photography surveying (photogrammetric survey) Surveying for 3D model generation Building Measurements and Structural Monitoring Setting out of buildings (building footprint) Facade measurements Deformation / settlement monitoring, inspection measurements Underground utility mapping survey

cadastral / stockpile / excavation / photogrammetry / generation / facade / utility / building setting out / footprint / deformation / monitoring / settlement / inspection

surveying tools / equipment / device / traditional / contemporary / state-of-the-art

Traditional and contemporary (state-of-the-art electronic devices) surveying tools

steel tape / chaining pins / spring tension / compass / optical square / ranging rods flag-pole / staff / theodolite / transit / total station / level / tripod

steel tapes

spring tension

theodolite

compass

ranging rods & flag-pole

optical square

chaining pins

tripod

staff

level

Tripods are used for several surveying instruments, such as theodolites, total stations, levels or transits.

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transit

They are the same thing. Europeans tend to say "theodolite", which is the older term. Americans tend to say "transit." Both theodolites and transits are instruments used by surveyors to measure horizontal and vertical angles, measure distances and determine elevations. Generally a theodolite is more precise in point of vernier increments and optical systems. It has more incrementations on the circle.

theodolite

vernier increments

theodolite / transit / total station / instrument / precise / vernier / optics

What is the difference between a theodolite and a transit?

The original theodolite was a purely optical instrument, but nowadays most theodolites come with an electronic distance-measuring attachment called as total station. Total stations possess automatic angle and distance readout capabilities.

What is the difference between a theodolite and a total station?

Theodolite Total station is a instrument having

theodolite / total station / instrument / attachment / installation / readout

Manual installation Manual reading of scales

Automatic readout capabilities Simple and quick installation on any ground Fast & easy data transfer to tablet PC or notebook

Theodolites can measure: Horizontal angles Vertical angles Distances Elevations

Levels can measure: Horizontal angles Distances Elevations

Measurement accuracy depends on many factors. Instrument error (Model and type of instrument) Human error (Surveyors’ skill) Natural error (Atmospheric conditions, wind speed, air temperature, atmospheric pressure, humidity, etc)

axis / measurement accuracy / error / skill / atmospheric condition / wind / humidity

What is the difference between a theodolite and a level?

What is the difference between a theodolite and a level?

leveling / control point / backsight reading / foresight reading

The bubble tube

Leveling with three foot screws

leveling / line of sight / horizontal / bubble tube / vial screw / lever / clamp / tribrach

How to set the line of sight (line of vision ) to be exactly horizontal?

high-tech / EDM / GPS / DGPS / global positioning system / differential / drone

EDM (Electronic Distance Measurement system) Total station equipped with EDM GPS (Global Positioning System) DGPS (Differential Global Positioning System) Drones for surveying

EDM

Total Station

Ordinary GPS

DGPS

Drone

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EDM / transmitter / receiver / wave / retroprism /reflector

EDM (Electronic Distance Measurement system)

Principle of EDM

EDM / total station / equipped / capability

Total station equipped with EDM (Optical and electronic measurement capabilities)

EDM

Total Station

GPS / satellite / space / maintain / transmission / signal / embedded/ position

GPS (Global Positioning System)

Regular GPS

24 Satellites in space, maintained by US Military

Each satellite transmits a signal with embedded time

GPS Unit receives signal and records time

Position is calculated using triangulation by determining how long each signal took to leave satellite and to then be received by the GPS unit

Regular GPS receiver

CORS-TR (Continuously Operating

Reference Stations) PROJECT

CORS-

TR® PROJECT

ESTABLISHMENT OF

NATIONAL CORS

SYSTEM AND DETERMINATION

OF DATUM

TRANSFORMATION

PARAMETERS

establishment / national / datum / continuously / operating / reference / station

DGPS / principle / accuracy / correction / unknown / approximation / position

DGPS (Differential GPS)

Regular GPS receiver

Standard GPS Accuracy Old was 100m accuracy

New is 15m

WAAS technology is less than 3m

The basic principle of DGPS is to remove these errors by determining the difference between the measured distance at an unknown point whose position is to be fixed and an approximation of the true distance as calculated by a receiver at a known position.

DGPS Units

drone / airborne / image / model / generation / software

Drones for surveying and 3D model generation

Everyday new software has been specifically created and released for generating 3D maps from drone images.

Drone

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topographic maps / marine works / bathymetric maps / seafloor map / sonar system

“Land surveying” for “Topographic maps" “Marine surveying” for “Bathymetric maps”

Drone

Bathymetric Sonar System

Marine works: Costal protection Ports and marinas Offshore structures

density / salinity / conductivity / tide / current / wave / wave gage / buoy

Physical oceanographic parameters (Density, salinity, etc) CTD (Conductivity, Temperature and Depth) Sea level variations Current velocity Wave heights

Drone

Short and long term measurements

Spatial data: Data check and filtering Corrections Calculations Plotting points Drawing contours

spatial data / data filtering / correction / plotting / contour

Mapping Technique Manual mapping Mapping software

Mapping Technique Manual mapping Mapping software

Spatial data: X,Y,Z Lat, Long, height (or depth) Mapping software such as Surfer, Grapher, MapInfo etc.

spatial data / latitude / longitude / contour map / terrain map / surface map

How do you measure approximately “the height of a building” without any surveying tool?